Sounds like you either weren't tired enough or weren't in a REM cycle.

70 minutes is too long. While your resolve is admirable If you're waiting longer than 30 minutes chances are it isn't going to happen. Be sure you're doing a WBTB (waking up in the middle of the night). If you're not, a lucid dream is nearly impossible. REM cycles get longer as you sleep and dreaming becomes easier later in the night.